Determination of the linear velocity of the gasU.K.
With the gas chromatograph set to normal operating conditions inject 1 to 3 μl of methane (or propane) and measure the time taken by the gas to pass through the column from the time of injection to the time at which the peak appears (tM).
The linear velocity in cm/s is given by L/tM, where L is the length of the column in centimetres and tM is the measured time in seconds.